Exploring the Stars, 3rd London Guides, April 4th, 2018

Cloudy, windy weather with snow flurries greeted 24 visitors (19 children and 5 adults / leaders) from the 3rd London Guides, for Exploring the Stars at Western University’s Cronyn Observatory, Wednesday, April 4th, 2018, 7:00 p.m. Graduate student Viraja Khatu made the digital slide presentation “The Scout / Guide Astronomy Badge,” with the title slide “The Basics,” and fielded questions. Viraja followed this with the “Constellations” activity, distributing 23 “Star Finder” planispheres, showing the visitors how to assemble them with adhesive tape, showing the slide “Reading a Star Finder” and demonstrating how to use them to locate constellations in the sky.

RASC London Centre was represented by Everett Clark, Henry Leparskas and Bob Duff. Weather conditions ruled out opening the dome. When everybody arrived upstairs in the dome, Bob gave a talk on some of the history of the observatory and technical aspects of the big 25.4cm refractor, using the 32mm Erfle eyepiece (137X) for demonstration. Bob explained how the Schmidt camera worked—demonstrating how the shutter opened and closed—as well as the Cassegrain reflector telescope piggy-backed on the 25.4cm refractor. He showed them the London Centre’s 25.4cm Dobsonian reflector set up in the dome and explained the difference between a refractor and reflector telescope. Bob also explained the 2 clocks on the east wall and the difference between Standard and Sidereal Time. To demonstrate how the dome moved, Bob removed the counterweight on the chain and Henry invited 2 of the girls to operate the control lever and move the dome.

The Guides were then invited to view the wind turbine on the Engineering building through the 25.4cm Dobsonian (17mm Nagler eyepiece, 66X) set up on a wheeled dolly, just inside the door to the observation deck. This was the first use of one of the two wooden “dollies” with wheels (casters) built by Henry to more easily move the London Centre’s Dobsonian telescopes at the Cronyn Observatory.

The Guides were then brought downstairs into the “Black Room” where they were divided into 2 groups for the “Spectroscopy Demonstration” and tour of the “1940s Period Room.” Viraja gave 2 demonstrations (one to each group) of the “Spectroscopy Demonstration,” with the visitors putting on diffraction grating glasses to view the spectra of 4 gas discharge lamps, including: hydrogen, helium, neon and mercury. The “Spectroscopy Demonstration” gas discharge lamps were mounted on the “Black Room” wall by Henry Leparskas on March 15th, 2018, so as to no longer take up table space.

Henry gave 2 tours (one to each group) of the historic “1940s Period Room,” a recreation of Dr. H. R. Kingston’s 1940 office (designed by RASC London member Mark Tovey), with Dr. Kingston’s brass refractor and the Sotellunium—a mechanical eclipse demonstration model built by W. G. Colgrove—on display. The Guides were greatly impressed by their tour of the observatory and signed the guest book in the “1940s Period Room” before leaving around 9:00 p.m.